Vacuum controlled air bleed valve



April 17, 1956 H. w. MccLAlN 2,742,270

VACUUM CONTROLLED AIR BLEED VALVE Filed Feb. 25, 1954 En su@Y nl Vif United States Patent() throttle 3. mounted in the tioat bowl 4 and extends vertically into vit 2,742,270 VACUUM coNTRoLLED AIRBLEED VALVE Harry w. Mechanism-Beatrix, Calif. Appli-marian February 2s, V1.954, seran N0.41V1,-s1`.7

s claims. (ci. zere-41)"y This invention relates to a vacuum controlled air bleed valve for carburetors, `the purpose of which Vis to prevent fuelilow in the idling orlow speed system ofV a carburetor when the vacuum Yrises above the normal idling vacuum inthe intakernanifold. This increased vacuum in-the intake manifold is caused by deceleration or coasting of the vehicle. p

An object of my Ainvention is to provide a novel vacuum lcontrolled air bleed yvalve which is adjustable so that it fold. i v

Another objectof my invention is to :provide a novel Y -will function at the required vacuum in the intake manip valve of the character stated, whichcan be quickly and easily attached to carburetors presently in use, and without requiring extensive reworkingor redesigning of the carburetor.

Still another object of my invention is to provide a novel yvalve of thecharacter stated, which is simple in construcoperation.

Other .objectaf-advantages and features of invention: l may appear .from the accompanying drawing, the sub` joined' detailed description and Vthe appended claims. the drawing: i

' igure-Jl' is a side elevation of a'carburetor with my bleed valve mounted theron `and with parts brokenaway y to show interior construction] I Figure 2 is a longitudinal sectional iview of my bleed Y valve with the slide valves in Vclosed position.

describe the carburetor and the idling fuel system, or low speed fuel system of the carburetor, all of which is usual and well known. The carburetor 1 includes the usual throat or intake pipe 2 in which the throttle valve 3 is mounted. The fuel bowl or float bowl 4 is mounted on one side of the pipe 2, and the fuel feeds into this bowl through the pipe 5. The idling or low speed fuel system includes a pipe 6 which opens into the pipe 2 below the This pipe extends into a tube 7 which is this bowl, and the lowerend of the tube is immersed in ythe fuel. Thus under' usual operation, the vacuum exerted `below the throttle valve 3 will draw fuel through the tube 7, thence into the pipe 6, and will feed the fuel into the pipe 2 Where it passes into the intake manifold of the engine. 4It will be evident that if the vacuum increases excessively below the throttle valve 3, that large quanv Vtities` of fuel will be drawn through the pipe 6, all of which tion, inexpensive to manufacture, and which is effective in Y stance the pipe 19 (which may be rubber) is slipped overl 2,742,270 Patented Apr.` 17, 1956 ICC 2 is detrimental to the engine. The excessive vacuum is caused by deceleration or coasting, as when a vehicle is going down a long hill when the throttle is closed.

To prevent excessive amounts of fuel from being drawn into the pipe 6, I provide the `following'structu're: A tubular valve housing 8 is mounted on the lloat bowl 4 by means of a clamp 9 whchencircles the housing. A centralwall 10 within the housing Ydivides the same into two ,cylinders or chambers 11-12. A piston 13 is slidably mounted in the cylinder k111 and a piston 14 is slidably mounted in the cylinder 12. A port 15Y extends through the wall 10 and opens into both of the cylinders 11 and 12. A pipe 16 extends from the port 15 to the pipe 2 below the throttle valve 3. Thus the vacuum below'the throttle valve'3 will be exerted through the port 15 to both cylinders 11 and 12. A spring 17 bears against the piston 13 and presses this piston against the outer end of the cylinder 11 and normally "seats the piston, as will be further described. A similar spring 18 bears against the piston 14 and presses the piston against the outer end of the cylinder 12. A pipe 19 extends from the outer end of the cylinder 11 to the pipe 6 and opens into the pipe 6 for the purpose of admitting atmospheric pressure to thev pipe 6,A ina manner to be subsequently described. The outer end of the piston 13 is provided with a seat 20 which seals against the outer end of the cylinder 11, normally closing the opening to the pipe 19 when the piston 13 is held pressed against the outer end of the cylinder 11.` A bleed port 21, open to the atmosphere, extends -into the outer end of the cylinder 11 but back of the seat 20, so that atmospheric pressure is only admitted to the pipe 19 when the piston ,13 is unseated. l

f When-atmospheric pressure is admitted to the'pipe;

fuel flow in the pipewill be broken since the vacuurn in the pipe 6 will be materially reduced and thus Vwill not drawfuel from the tube 7. A conduit 22 extendsV from the outer end of the cylinder 12 and thence into the top of the iloat bowl 4. vThe piston 14 is provided with a valve Vseat 23, which normally rests against the outer end of the `cylinder 12 to close the opening to the conduit 22. A 'bleed port 24 extends through the piston'14 back ofi the valve seat 2 3, and this bleed port extends intothe inner end ofthe cylinder 12 so that vacuum can be exerted through this bleed port, thence through the conduit 22 and thenceto the float bowl 4, so that a vacuum will be drawn on top of the float bowl 4 when the piston 14 is un-A the valve 25 for the same purpose of balancing the vacuum in the idling system andpreventing excessive fuel from being drawn into the carburetor. The connection ofthe pipe 22 into the float bowl 4 may` befacilitated by means of the valve attachment 27, which screws into the top of the oat bowl and iskprovided with a spring pressed valve normal, for example, duringV idling speeds of the engine,

the springs 17 and 18 will hold the pistons 13 and 14 seated against the outer ends of the cylinders 11 and 12, respectively. The normal idling fuel will now be drawn through the pipe 6 and through the tube 7 in a normal manner, whenever the vacuum increases below the throtztlc 3, so that the springs 17--18 will be compressed and Vthe pistons 13 and 14 will be drawn inwardly, as shown in Figure 3. In this position of the pistons atmospheric air is drawn through the bleed port 21 and feeds air under atmospheric pressure through the pipe 19 and into the pipe 6. This breaks the vacuum in the pipe 6 and fuel will cease to ow through this pipe and thence into the throat 2 of the carburetor. At the same time a reduced air pressure is maintained on one side o the, piston 14. This re- -duced pressure is exerted through the port 24 and thence through the pipe 22, so that the float bowl 4 will be parl. in a carburetor including an intake pipe, a throttle in the intake pipe, a oat bowl, an idling fuel pipe extending from the float bowl into the intake pipe below the throttle, a vacuumcontrolled air bleed valve comprising a housing, said housing having a cylinderl therein, a iirst piston in the cylinder, said piston seating against one end of the cylinder, air bleed means adjacent the piston seat yand said air bleed means being opened when the piston is unseated, a second piston in the cylinder, the secondpiston seating against the other end of the cylinder, a pair of springs, each spring bearing against one of said pistons and urging the pistons against their seats, a vacuum pipe extending from the intake pipe of the carburetor to said cylinder, another pipe extending from the cylinder at the end against which the first piston seats and thence into the idling fuel pipe to admit atmospheric air to the idling fuel pipe, a conduit extending from the other end of the cylin-Y der and thence into the float bowl of the carburetor, said second piston having a vacuum port therein, said vacuum lport being open to said conduit when the second piston is unseated.`

2. In a carburetor including an intake pipe, a throttle in the intake pipe, a iloat bowl, an idling fuel pipe extending from the iloat bowl to the intake pipe below the throting, said housing having a cylinder therein, a rst piston in the cylinder, said first piston seating against one end of the cylinder, said housing having an air bleed port therein between the rst piston and the seat in the cylinder, a

`tle, a vacuum controlled air bleed valve comprising a hous- Second piston in the cylinder, the second piston seating against, the other end of the cylinder, a pair of springs each bearing against one of the pistons and urging the pistons against their seats, a vacuum pipe extending from said intake pipe of the carburetor to saidl cylinder, another pipe extending from the cylinder at the end against which the iirst piston seats and thence into the idling fuel pipe, a conduit extending from the other end of the cylinder and thence into the oat bowl of the carburetor, said second piston 'having a bleed port extending therethrough, the bleed port being open when the second'piston is unseated, said bleed port opening into the cylinder whereby a vacuum is -drawn in-the conduit and iioat bowl when the piston is unseated.

3. In a carburetor including an intake pipe, a throttle in the intake pipe, a iioat bowl, an idling fuel pipe extending from the float bowl to the intake pipe below the throttle, a vacuum controlled air bleed valve comprising a housing, a central wall in the housing, said housing having a cylinder therein on each side of the central wall, a piston in each cylinder, said pistons each seating against the outer ends of the cylinders, said housing having an air bleed port therein between the rst piston and the seat in the'cylinder, a pair of springs, each spring bearing against one of the pistons and urging the pistons against their seats, a vacuum pipe extending from theintake pipe of the carburetor and thence into the central Wall, said central 'wall having av-port extending therethrough into each of the cylinders, and said port communicating with the vacuum pipe, another pipe extending from the outer end of the cylinder against which the first piston seats and thence into the idling fuel pipe, a conduit extending from the outer end of the other cylinder and against which the second piston seats, said conduit extending into the oat bowl, the last named piston having a bleed port extending therethrough to evacuate the conduit and the tloat bowl when the last named piston is unseated.l i

References Cited in the tile of this patent 

